1. Field of the Invention
Embodiments of the present invention relate to compositions and methods for the production, purification, formulation, and use of eubacterial minicells as targeted delivery vehicles for in vivo and in vitro nucleic acid, protein, and small molecule drug delivery as well as a targeted in vivo imaging and diagnostic technology.
2. Description of the Related Art
The following description is provided to aid in understanding the present disclosure, but is not admitted to describe or constitute prior art to the present disclosure. The contents of the articles, patents, and patent applications, and all other documents and electronically available information mentioned or cited in this application, are hereby incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. Applicants reserve the right to physically incorporate into this application any and all materials and information from any such articles, patents, patent applications, or other documents.
Minicells are achromosomal, membrane-encapsulated biological nano-particles (≦400 nm) that are formed by bacteria following a disruption in the normal division apparatus of bacterial cells. In essence, minicells are small, metabolically active replicas of normal bacterial cells with the exception that they contain no chromosomal DNA and as such, are non-dividing and non-viable. Although minicells do not contain chromosomal DNA, plasmid DNA molecules, RNA molecules, native and/or recombinantly expressed proteins, and other metabolites have all been shown to segregate into minicells.
Throughout the last century, minicells have been exploited as tools for research scientists studying cell division, plasmid replication, plasmid segregation, RNA production, protein production, plasmid isolation, plasmid characterization, and plasmid-borne virulence factor production in prokaryotes.
As a result of advances in the fields of microbiology, microbial genetics, and molecular biology, any given minicell, regardless of the parental cell species from which it was derived, can now be engineered and subsequently used as in vivo or in vitro targeted delivery or imaging vehicles.
Minicells are uniquely suited as in vivo delivery and imaging vehicles because they combine many of the singular advantages of other delivery technologies into a single, versatile delivery vehicle. Minicells can be “engineered” to preferentially encapsulate, be coupled to, or absorb biologically active molecules, including various nucleic acids, proteins, and small molecule drugs for subsequent delivery in both therapeutic and prophylactic medicinal applications. As described in much more detail below, minicells have the added advantage in that they can be targeted to specific cell, tissue, and organ types, through the use of several different antibody or affinity-based approaches.